Datasheet

Section 22 Flash Memory
Rev. 3.00 Sep. 28, 2009 Page 717 of 910
REJ09B0350-0300
MAT switching is enabled by writing a specific value to FMATS. Note, however, that while the
MATs are being switched, the LSI is in an unstable state, e.g. access to a MAT is not allowed until
MAT switching is completed, and if an interrupt occurs, from which MAT the interrupt vector is
read is undetermined. Perform MAT switching in accordance with the description in section
22.10, Switching between User MAT and User Boot MAT.
Except for MAT switching, the programming procedure is the same as that in user program mode.
The area that can be executed in the steps of the user procedure program (on-chip RAM and user
MAT) is shown in section 22.8.4, Storable Areas for On-Chip Program and Program Data.
(3) User MAT Erasing in User Boot Mode
For erasing the user MAT in user boot mode, additional processing made by setting FMATS are
required: switching from user-boot-MAT selection state to user-MAT selection state, and
switching back to user-boot-MAT selection state after erasing completes.
Figure 22.15 shows the procedure for erasing the user MAT in user boot mode.